Komine-Abe Ayano, Nagano-Shoji Megumi, Kubo Shosei, Kawasaki Hisashi, Yoshida Minoru, Nishiyama Makoto, Kosono Saori
a Biotechnology Research Center , The University of Tokyo , Tokyo , Japan.
b Kyowa Hakko Bio Co., Ltd , Tokyo , Japan.
Biosci Biotechnol Biochem. 2017 Nov;81(11):2130-2138. doi: 10.1080/09168451.2017.1372182. Epub 2017 Sep 13.
In Corynebacterium glutamicum, the activity of the 2-oxoglutarate dehydrogenase (ODH) complex is negatively regulated by the unphosphorylated form of OdhI protein, which is critical for L-glutamate overproduction. We examined the potential impact of protein acylation at lysine (K)-132 of OdhI in C. glutamicum ATCC13032. The K132E succinylation-mimic mutation reduced the ability of OdhI to bind OdhA, the catalytic subunit of the ODH complex, which reduced the inhibition of ODH activity. In vitro succinylation of OdhI protein also reduced the ability to inhibit ODH, and the K132R mutation blocked the effect. These results suggest that succinylation at K132 may attenuate the OdhI function. Consistent with these results, the C. glutamicum mutant strain with OdhI-K132E showed decreased L-glutamate production. Our results indicated that not only phosphorylation but also succinylation of OdhI protein may regulate L-glutamate production in C. glutamicum.
在谷氨酸棒杆菌中，2-氧代戊二酸脱氢酶（ODH）复合物的活性受到未磷酸化形式的OdhI蛋白的负调控，这对于L-谷氨酸的过量生产至关重要。我们研究了谷氨酸棒杆菌ATCC13032中OdhI的赖氨酸（K）-132位点蛋白质酰化的潜在影响。K132E琥珀酰化模拟突变降低了OdhI与ODH复合物催化亚基OdhA结合的能力，这降低了对ODH活性的抑制。OdhI蛋白的体外琥珀酰化也降低了抑制ODH的能力，并且K132R突变阻止了这种作用。这些结果表明，K132位点的琥珀酰化可能减弱OdhI的功能。与这些结果一致，具有OdhI-K132E的谷氨酸棒杆菌突变株显示L-谷氨酸产量下降。我们的结果表明，不仅OdhI蛋白的磷酸化，而且其琥珀酰化也可能调节谷氨酸棒杆菌中L-谷氨酸的产生。
